The Administrative and Research Core units will serve each of the Projects of the Program. In addition, these units will be a resource for grant supported research projects and protocols related to the overall goals of the participating laboratories. Dr. Galaburda, as Director of the Administrative Core (Core A), is the origin and clearing house of ideas that link the projects together, suggests coordinated changes, represents the Program to other institutions and programs, and motivates plans for future research and external collaborations. Dr. Galaburda will also review experimental design and data management, appropriate neurobehavioral instruments, ethical issues concerning animals, and budgetary effects on the Core units. The Executive Committee, which is composed of Drs. Galaburda, LoTurco, Fitch, and Rosen, will also review and advise on publications and meeting participation. The use of the Core budgetary resources will be at the discretion of the Core Director. Any redistribution of funds will require the approval of the Program Director. The use of the Cores is summarized in Table 1. The In Utero Electroporation Core (Core B) is located at the University of Connecticut and directed by Dr. Joseph J. LoTurco. This Core will be responsible for providing Research Projects with embryonicallytransfected live animals (Projects I and III) or perfused brains (Projects I and II). The Neurohistology, Morphometry, and Data Processing Core (Core C) is located at the applicant institution (Beth Israel Deaconess Medical Center) and is directed by Dr. Glenn D. Rosen. The Core will histologically process animals arising in the various research components, will morphometrically assess these brains, and will maintain a database of all animals being used in the Program Project.